Efficiency of the use of pock size on the chorioallantoic membrane of fertile hen's eggs as a method of typing herpes simplex viruses

Abstract

SUMMARYOne hundred and eighteen herpes simplex virus isolates were typed in a 'diagnostic virology laboratory using their standard procedure by pock size on the chorioallantoic membranes (CAMs) of fertile hen's eggs. Forty-three were typed as type 1 and 75 as type 2. The isolates were then sent to a research laboratory in which they were typed blind, with or without subsequent passage in tissue culture, by neutralization with type-specific antisera. Discrepant results were found with only two isolates. The isolates were then typed by the more time-consuming but unambiguous method of restriction endonuclease analysis of their DNAs. Typing by this method confirmed the typing by neutralization and established that typing by pock size on CAMs was correct in about 98 % of cases.

A simple biological marker to differentiate the types of Herpes Simplex Viruses in resource-limited settings

“…This was probably because the work was done with high passage laboratory strains rather than low passage clinical isolates, since repeated passage of HSV isolates tend to diminish the distinctive properties of the two types by means of selection and mutation. Another study from the UK which had adopted HSV isolates by egg passage first reported that the size of pocks produced by HSV-2 were 0.8-1 mm, while HSV-1 were 0.2-0.5mm 18 , which is comparable to our findings. Similarly, other studies to differentiate HSV isolates from clinical samples by pock size observed that pocks produced by HSV-2 isolates were comparatively larger (>0.5 mm) while HSV-1 were smaller (<0.5mm) 15,17 .…”